An Innovative Method of Obtaining Herbal Propolis Extracts and Application of its Spray-Dried Form as Natural Food Preservatives.

An innovative method of production of the herbal propolis extract (PE) with a masked scent of propolis suitable for food applications was proposed. The obtained extracts based on propolis and selected dried herbs were compared in terms of antioxidant activity, the polyphenolic profile (HPLC), and the volatile fraction (GC × GC-MS, olfactometry), as well as antibacterial activity against Streptococcus spp. using serial microdilution method. Based on the highest content of polyphenols and richer volatile fraction, pure PE and Herbes de Provance propolis extract (HPPE) were fractionated by vacuum concentration, obtaining two fractions: hydrophilic and hydrophobic which showed differing antimicrobial effects. Full extracts and fractions were powdered by spray-drying. The positive effect of herbs additive on the powder morphology was confirmed by scanning electron microscopy (SEM) analysis. Good retention of phenolic and volatile components in the obtained powders was demonstrated; however, the composition of powdered fraction was different. Although the antimicrobial activity of powders was not observed in vitro, the first effective attempts were made to use full extracts both in liquid and powdered forms to extend the shelf life of chicken breasts and apple juice. HPPE compared to PE extract turned to be more effective as a preservative, so the proposed method can increase the use of propolis in food preservation.